Drywall is used in the construction of buildings. It is plasterboard made of gypsum and other ingredients and is sold in sheets of, typically, 4 feet by 8 feet. It is used for covering wall studs and is then covered with, for example, paint or wallpaper. Drywall needs to be sized to be used for most applications. Although drywall is easy to cut by scoring the drywall and then “snapping” the drywall at the score mark, it is often cumbersome to make properly measured straight score marks and breaks. This is because the tools used to permit the scoring and cutting of an eight foot piece of drywall must be just as long as the longest length of the drywall (i.e., eight feet) or the user must make score marks from both ends of the drywall and try to align the score marks. Such techniques are cumbersome because the tools presently available to workers do not permit the easy of use necessary for quick and accurate scoring and cutting of drywall. In addition, the tools presently available to workers in the field do not permit the easy repositioning of the tool when setting up to make the needed score marks and cuts. This leads to inaccuracy and wastes time.
Today, drywall is typically cut with a straight edge and a utility knife. Sometimes people use T-squares or other devices to help ensure that the score marks and breaks are straight. Others have designed devices to aid users in the scoring and cutting of drywall but these prior art solutions to this problem are not without significant problems of their own.
For example, U.S. Pat. No. 4,956,919 to Granger discloses a drywall T-square with perpendicular members that slide relative to each other and with slots cut into the long arm of the T-square for inserting a knife blade. The user must then slide the T-square across the top of the drywall or slide one arm of the T-square within the other arm while simultaneously maintaining the cutting edge of the knife perpendicular to the drywall sheet. As can be seen, this device makes the scoring and cutting of drywall both cumbersome and prone to error.
U.S. Pat. No. 5,600,892 to Peugh, et al., discloses a drywall cutter for simultaneously scoring on both sides of the plasterboard. The cutter has two long arms that must be slipped over the end of the drywall carefully and evenly to avoid breaking or damaging the drywall causing waste or necessitating repairs. Such manipulations are cumbersome and only serve to slow workers down.
U.S. Pat. No. 5,471,753 to Rodrigues discloses a T-square style drywall cutter with a sliding knife-edge. If the device is not placed in the correct location for cutting it must be moved across the top of the drywall sheet. This is not always easy to accomplish as the T-square will tend to drag on the drywall sheet requiring the user to lift the device off of the drywall sheet and replace it. This, of course, it time consuming for the user.
U.S. Pat. No. 6,070,331 to Dempsey discloses a T-square with tabs that work to keep the device from rocking as it is being used. The device, however, has the same problems as the device discussed directly above. That is, if it must be moved it will drag across the edge of the drywall requiring the user to lift the device off of the drywall sheet and replace it. This, of course, it time consuming for the user.
U.S. Pat. No. 6,629,370 to Sposato describes a T-square having a slidable knife and stabilizer tabs. The device, however, has the same problems as the devices discussed directly above. That is, if it must be moved it will drag across the edge of the drywall requiring the user to lift the device off of the drywall sheet and replace it. This, of course, it time consuming for the user. Additionally, the mechanism for holding the knife blade is complicated, cumbersome to use and prone to loosening during use.
Therefore, what is needed is a drywall cutter that solves these prior art problems. Namely, what is needed is a drywall cutter that moves across the edge of the drywall easily as well as having a slidable knife that is both easy to use and does not easily loosen during use.